Apparatus to reduce bearing failure

This application arises as a continuation of U.S. patent application Ser. No. 18/356,690 (now U.S. Pat. No. 12,281,657), filed on Jul. 21, 2023, which claims priority to and the benefit of Indian patent application Ser. No. 202211073553, filed on Dec. 19, 2022. U.S. patent application Ser. No. 18/356,690 and Indian patent application Ser. No. 202211073553 are hereby incorporated herein by reference in their entireties. Priority to U.S. patent application Ser. No. 18/356,690 and Indian patent application Ser. No. 202211073553 is hereby claimed.

This disclosure relates generally to fluid pumps and, more particularly, to an apparatus to reduce bearing failure.

Aircraft typically include various accessory systems supporting the operation of the aircraft and/or its gas turbine engine(s). For example, such accessory systems may include a lubrication system that lubricates components of the engine(s), an engine cooling system that provides cooling air to engine components, an environmental control system that provides cooled air to the cabin of the aircraft, and/or the like. Such accessory systems also include bearings of various types to enable proper operation of the accessory systems.

In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. The figures are not to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. Although the figures show layers and regions with clean lines and boundaries, some or all of these lines and/or boundaries may be idealized. In reality, the boundaries and/or lines may be unobservable, blended, and/or irregular.

“Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim employs any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, having, etc.) as a preamble or within a claim recitation of any kind, it is to be understood that additional elements, terms, etc., may be present without falling outside the scope of the corresponding claim or recitation. As used herein, when the phrase “at least” is used as the transition term in, for example, a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” are open ended. The term “and/or” when used, for example, in a form such as A, B, and/or C refers to any combination or subset of A, B, C such as (1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) B with C, or (7) A with B and with C. As used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B.

As used herein, unless otherwise stated, the term “above” describes the relationship of two parts relative to Earth. A first part is above a second part, if the second part has at least one part between Earth and the first part. Likewise, as used herein, a first part is “below” a second part when the first part is closer to the Earth than the second part. As noted above, a first part can be above or below a second part with one or more of: other parts therebetween, without other parts therebetween, with the first and second parts touching, or without the first and second parts being in direct contact with one another.

As used herein, singular references (e.g., “a”, “an”, “first”, “second”, etc.) do not exclude a plurality. The term “a” or “an” object, as used herein, refers to one or more of that object. The terms “a” (or “an”), “one or more”, and “at least one” are used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method actions may be implemented by, e.g., the same entity or object. Additionally, although individual features may be included in different examples or claims, these may possibly be combined, and the inclusion in different examples or claims does not imply that a combination of features is not feasible and/or advantageous.

As used in this patent, stating that any part (e.g., a layer, film, area, region, or plate) is in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, indicates that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween.

As used herein, connection references (e.g., attached, coupled, connected, and joined) may include intermediate members between the elements referenced by the connection reference and/or relative movement between those elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and/or in fixed relation to each other. As used herein, stating that any part is in “contact” with another part is defined to mean that there is no intermediate part between the two parts.

Unless specifically stated otherwise, descriptors such as “first,” “second,” “third,” etc., are used herein without imputing or otherwise indicating any meaning of priority, physical order, arrangement in a list, and/or ordering in any way, but are merely used as labels and/or arbitrary names to distinguish elements for ease of understanding the disclosed examples. In some examples, the descriptor “first” may be used to refer to an element in the detailed description, while the same element may be referred to in a claim with a different descriptor such as “second” or “third.” In such instances, it should be understood that such descriptors are used merely for identifying those elements distinctly that might, for example, otherwise share a same name.

As used herein, “approximately” and “about” modify their subjects/values to recognize the potential presence of variations that occur in real world applications. For example, “approximately” and “about” may modify dimensions that may not be exact due to manufacturing tolerances and/or other real world imperfections as will be understood by persons of ordinary skill in the art. For example, “approximately” and “about” may indicate such dimensions may be within a tolerance range of +/−10% unless otherwise specified in the below description.

The terms “forward” and “aft” refer to relative positions within a gas turbine engine, pump, or vehicle, and refer to the normal operational attitude of the gas turbine engine, pump, or vehicle. For example, with regard to a gas turbine engine, forward refers to a position closer to an engine inlet and aft refers to a position closer to an engine nozzle or exhaust. Further, with regard to a pump, forward refers to a position closer to a pump inlet and aft refers to a position closer to an end of the pump opposite the inlet.

The terms “upstream” and “downstream” refer to the relative direction with respect to a flow in a pathway. For example, with respect to a fluid flow, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.

As used herein, “radially” is used to express a point or points along a radial vector originating at a central axis of a rotating body and pointing perpendicularly outward from the central axis. In some examples, two gears are said to be radially connected or coupled, meaning that the two gears are in physical contact with each other at point(s) along the circumferential outer edge surface of the gears via interlocking gear teeth. In some examples, two pulleys are said to be radially connected or coupled, meaning that the two pulleys are in physical contact with a drive belt at point(s) along the circumferential outer edge surface of the pulleys.

Centrifugal fluid pumps move fluid through systems by converting rotational kinetic energy of an impeller to hydrodynamic energy of a flowing fluid. In other words, the angular velocity of the impeller is directly proportional to the flow rate of the flowing fluid exiting the pump. The impeller provides a change in rotational kinetic energy from an electric motor applying mechanical work to an impeller shaft coupled to the impeller and to the rotor of the electric motor. The rotor is provided a change in mechanical work over a period of time (i.e., mechanical power) from a stator in the electric motor applying electromagnetic forces to the rotor in the form of torque. If the motor supplies a constant amount of electrical energy to the stator, then the rotor will supply a constant amount of mechanical energy to the impeller. In this case, the mechanical power supplied to the pump by the electric motor would be equal to the quotient of the rotational kinetic energy and the amount of time the power is being supplied. In rotational systems, such as a centrifugal fluid pump, the mechanical power of the impeller is equal to the product of the torque and the angular velocity. If the rotor of the electric motor and the impeller shaft of the centrifugal fluid pump are coupled axially (e.g., by a magnetic coupling), then the torque and angular velocity of the rotor would transfer to the impeller, via the coupled shafts, and would be of the same values.

In some examples of fluid pump systems, a motor shaft (e.g., a rotor) can be axially coupled to an impeller shaft via a magnetic coupling. Magnetic couplings transfer torque between two shafts without physical contact between the shafts. In some examples, the magnetic coupling can be in the form of an inner hub fastened to a first shaft (e.g., an impeller shaft) and an outer hub fastened to a second shaft (e.g., a rotor shaft). In the example outer hub, there are a series of magnets (e.g., bar magnets) positioned to surround the example inner hub with each magnet having an opposite charge of the preceding magnet in the series. In the inner hub, a similar series of magnets are positioned around an axis of rotation of the first shaft. In some examples, the outer hub and inner hub have the same number of magnets. Because magnets of opposite charges are attracted to each other via magnetic fields, when the outer hub is positioned around the inner hub, a rotation of the outer hub causes the inner hub to rotate at the same rate. In other words, the example inner hub and the example outer hub are rotatably interlocked. This type of magnetic coupling can be referred to as a co-axial magnetic coupling. Because there is no physical contact between the inner hub and outer hub of the co-axial magnetic coupling, a containment barrier can be fastened to the housing surrounding the inner hub such that no fluid can pass from the inner hub side to the outer hub side.

Foil bearings are included in fluid pump systems to act as buffers preventing shafts (e.g., a rotor shaft, a radial shaft, etc.) from contacting with a lining surrounding the shaft and allowing relative motion between the shaft and the lining. In some examples, the foil bearing may become damaged when the shaft exerts too much force on the foil bearing, causing permanent deformation to the foil bearing and ultimately causing damage to the pump system. In such an example, the foil bearing is rated to support a load applied to the foil bearing by the shaft, and when the shaft exceeds that load, the foil bearing becomes damaged.

Certain examples provide an improved bearing design that resists damage caused by the forces applied by aircraft engines, the forces of flight of an aircraft, and the forces applied by pump systems. As discussed further below, certain examples provide an improved bearing design to improve the integrity, stability, and reliability of bearings used in apparatus such as the aircraft, engine, and pump described below.

is a side view of an example aircraft. As shown, the aircraftincludes a fuselageand a pair of wings(one is shown) extending outward from the fuselage. In the illustrated example of, a gas turbine engineis supported on each wingto propel the aircraft through the air during flight. Additionally, as shown, the aircraftincludes a vertical stabilizerand a pair of horizontal stabilizers(one is shown). However, in alternative examples, the aircraftmay be configured differently, such as with a different number and/or type of engines.

Furthermore, the aircraftmay include a thermal management systemfor transferring heat between fluids supporting the operation of the aircraft. More specifically, the aircraftmay include one or more accessory systems configured to support the operation of the aircraft. For example, such accessory systems include a lubrication system that lubricates components of the engines, a cooling system that provides cooling air to components of the engines, an environmental control system that provides cooled air to the cabin of the aircraft, and/or the like. In such examples, the thermal management systemis configured to transfer heat to and/or from one or more fluids supporting the operation of the aircraft(e.g., the oil of the lubrication system, the air of the cooling system and/or the environmental control system, and/or the like) from and/or to one or more other fluids supporting the operation of the aircraft(e.g., the fuel supplied to the engines). However, in alternative examples, the thermal management systemmay be configured to transfer heat between other fluids supporting the operation of the aircraft.

In addition to the thermal management system, the aircraftis subjected to various forces during operation which include aerodynamic forces (e.g., lift, thrust, drag, gravity), vibration forces, shear forces, etc. As such, components within the aircraft(e.g., such as the example thermal management system, the engine, etc.) need to withstand such forces without failure to ensure the aircraftfunctions properly. Failure to the thermal management systemdue to excessive forces can lead to failure of the engineor failure to other systems on the aircraft.

The configuration of the aircraftdescribed above and shown inis provided only to place the present subject matter in an example field of use. Thus, the present subject matter may be readily adaptable to any manner of aircraft and/or any other suitable heat transfer application.

is a schematic cross-sectional view of an example gas turbine engine. In the illustrated example, the engineis configured as a high-bypass turbofan engine. However, in alternative examples, the enginemay be configured as a propfan engine, a turbojet engine, a turboprop engine, a turboshaft gas turbine engine, or any other suitable type of gas turbine engine.

In general, the engineextends along an axial centerlineand includes a fan, a low-pressure (LP) spool, and a high pressure (HP) spoolat least partially encased by an annular nacelle. More specifically, the fanmay include a fan rotorand a plurality of fan blades(one is shown) coupled to the fan rotor. In this respect, the fan bladesare circumferentially spaced apart and extend radially outward from the fan rotor. Moreover, the LP and HP spools,are positioned downstream from the fanalong the axial centerline. As shown, the LP spoolis rotatably coupled to the fan rotor, thereby permitting the LP spoolto rotate the fan blades. Additionally, a plurality of outlet guide vanes or strutscircumferentially spaced apart from each other and extend radially between an outer casingsurrounding the LP and HP spools,and the nacelle. As such, the strutssupport the nacellerelative to the outer casingsuch that the outer casingand the nacelledefine a bypass airflow passagepositioned therebetween.

The outer casinggenerally surrounds or encases, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In some examples, the compressor sectionmay include a low-pressure (LP) compressorof the LP spooland a high-pressure (HP) compressorof the HP spoolpositioned downstream from the LP compressoralong the axial centerline. Each compressor,may, in turn, include one or more rows of stator vanesinterdigitated with one or more rows of compressor rotor blades. As such, the compressors,define a compressed air flow pathextending therethrough. Moreover, in some examples, the turbine sectionincludes a high-pressure (HP) turbineof the HP spooland a low-pressure (LP) turbineof the LP spoolpositioned downstream from the HP turbinealong the axial centerline. Each turbine,may, in turn, include one or more rows of stator vanesinterdigitated with one or more rows of turbine rotor blades.

Additionally, the LP spoolincludes the low-pressure (LP) shaftand the HP spoolincludes a high pressure (HP) shaftpositioned concentrically around the LP shaft. In such examples, the HP shaftrotatably couples the turbine rotor bladesof the HP turbineand the compressor rotor bladesof the HP compressorsuch that rotation of the turbine rotor bladesof the HP turbinerotatably drives the compressor rotor bladesof the HP compressor. As shown, the LP shaftis directly coupled to the turbine rotor bladesof the LP turbineand the compressor rotor bladesof the LP compressor. Furthermore, the LP shaftis coupled to the fanvia a gearbox. In this respect, the rotation of the turbine rotor bladesof the LP turbinerotatably drives the compressor rotor bladesof the LP compressorand the fan blades.

In some examples, the enginemay generate thrust to propel an aircraft. More specifically, during operation, air (indicated by arrow) enters an inlet portionof the engine. The fansupplies a first portion (indicated by arrow) of the airto the bypass airflow passageand a second portion (indicated by arrow) of the airto the compressor section. The second portionof the airfirst flows through the LP compressorin which the compressor rotor bladestherein progressively compress the second portionof the air. Next, the second portionof the airflows through the HP compressorin which the compressor rotor bladestherein continue to progressively compress the second portionof the air. The compressed second portionof the airis subsequently delivered to the combustion section. In the combustion section, the second portionof the airmixes with fuel and burns to generate high-temperature and high-pressure combustion gases. Thereafter, the combustion gasesflow through the HP turbinewhich the turbine rotor bladesof the HP turbineextract a first portion of kinetic and/or thermal energy therefrom. This energy extraction rotates the HP shaft, thereby driving the HP compressor. The combustion gasesthen flow through the LP turbinein which the turbine rotor bladesof the LP turbineextract a second portion of kinetic and/or thermal energy therefrom. This energy extraction rotates the LP shaft, thereby driving the LP compressorand the fanvia the gearbox. The combustion gasesthen exit the enginethrough the exhaust section.

As mentioned above, the aircraftmay include a thermal management systemfor transferring heat between fluids supporting the operation of the aircraft. In this respect, the thermal management systemmay be positioned within the engine. For example, as shown in, the thermal management systemis positioned within the outer casingof the engine. However, in alternative examples, the thermal management systemmay be positioned at any other suitable location within the engine.

Furthermore, in some examples, the enginedefines a third-stream flow path. In general, the third-stream flow pathextends from the compressed air flow pathdefined by the compressor sectionto the bypass airflow passage. In this respect, the third-stream flow pathallows a portion of the compressed airfrom the compressor sectionto bypass the combustion section. More specifically, in some examples, the third-stream flow pathmay define a concentric or non-concentric passage relative to the compressed air flow pathdownstream of one or more of the compressors,or the fan. The third-stream flow pathmay be configured to selectively remove a portion of compressed airfrom the compressed air flow pathvia one or more variable guide vanes, nozzles, or other actuable flow control structures. In addition, as will be described below, in some examples, the thermal management systemmay transfer heat to the air flowing through the third-stream flow path. However, a pressure and/or a flow rate of a fluid (e.g., a heat exchange fluid such as a supercritical fluid (e.g., supercritical carbon dioxide (sCO2), etc.)) within the thermal management systemlimits a rate at which thermal energy is transferred between the air and the heat exchange fluid. Additionally, it is advantageous for the thermal management systemto produce the pressure and/or the flow rate with components (e.g., pump systems) that minimize and/or otherwise reduce a physical size of the thermal management systemand/or the components (e.g., pump systems) included therein. Moreover, the thermal management systemmay ensure that the heat exchange fluid is free of contaminants when thermal energy is to be transferred.

The example thermal management system, as described above, ensures proper operation of the aircraft. As such, the thermal management systemmust be operational to support the operation of the aircraft. The thermal management systemcan include a pump system to move fluid throughout the thermal management systemto support heat transfer functionality. Pump systems can include bearings which support the operation of the pump system. As disclosed above, failure of bearings in pump systems can occur where the bearings are subjected to excessive forces (e.g., vibration, shear, stress, etc.) beyond what the bearings are rated for, and thus, can cause failure to the pump system. Consequently, failure to the pump system can cause failure to the thermal management systemand, likewise, failure to the engine.

The configuration of the gas turbine enginedescribed above and shown inis provided only to place the present subject matter in an example field of use. Thus, the present subject matter may be readily adaptable to any manner of gas turbine engine configuration, including other types of aviation-based gas turbine engines, marine-based gas turbine engines, and/or land-based/industrial gas turbine engines.

is a schematic view of an example implementation of the thermal management systemfor transferring heat between fluids. In general, the thermal management systemwill be discussed in the context of the aircraftand the gas turbine enginedescribed above and shown in. However, the disclosed thermal management systemmay be implemented within other aircraft and/or any gas turbine engine configuration.

As shown, the thermal management systemincludes a thermal transport bus. Specifically, in several examples, the thermal transport busis configured as one or more fluid conduits through which a fluid (e.g., a heat exchange fluid) flows. As will be described below, the heat exchange fluid flows through various heat exchangers such that heat is added to and/or removed from the heat exchange fluid. In this respect, the heat exchange fluid may be any suitable fluid, such as supercritical carbon dioxide. Moreover, in such examples, the thermal management systemincludes a pumpconfigured to pump the heat exchange fluid through the thermal transport bus.

Additionally, the thermal management systemincludes one or more heat source heat exchangersarranged along the thermal transport bus. More specifically, the heat source heat exchanger(s)is fluidly coupled to the thermal transport bussuch that the heat exchange fluid flows through the heat source heat exchanger(s). In this respect, the heat source heat exchanger(s)is configured to transfer heat from fluids supporting the operation of the aircraftto the heat exchange fluid, thereby cooling the fluids supporting the operation of the aircraft. Thus, the heat source heat exchanger(s)adds heat to the heat exchange fluid. Althoughillustrates two heat source heat exchangers, the thermal management systemmay include a single heat source heat exchangeror three or more heat source heat exchangers.

The heat source heat exchanger(s)may correspond to any suitable heat exchanger(s) that cool a fluid supporting the operation of the aircraft. In one example, at least one of the heat exchangersis a heat exchanger(s) of the lubrication system(s) of the engine(s). In such an example, this heat exchanger(s)transfers heat from the oil lubricating the engine(s)to the heat transfer fluid. In another example, at least one of the heat exchangersis a heat exchanger(s) of the cooling system of the engine(s). In such an example, this heat exchanger(s)transfers heat from the cooling air bled from the compressor section(s)(or a compressor discharge plenum) of the engine(s)to the heat transfer fluid. However, in alternative examples, the heat source heat exchanger(s)may correspond to any other suitable heat exchangers that cool a fluid supporting the operation of the aircraft.

Furthermore, the thermal management systemincludes a plurality of heat sink heat exchangersarranged along the thermal transport bus. More specifically, the heat sink heat exchangersare fluidly coupled to the thermal transport bussuch that the heat exchange fluid flows through the heat sink heat exchangers. In this respect, the heat sink heat exchangersare configured to transfer heat from the heat exchange fluid to other fluids supporting the operation of the aircraft, thereby heating the other fluids supporting the operation of the aircraft. Thus, the heat sink heat exchangersremove heat from the heat exchange fluid. Althoughillustrates two heat sink heat exchangers, the thermal management systemmay include three or more heat sink heat exchangers.

The heat sink heat exchangersmay correspond to any suitable heat exchangers that heat a fluid supporting the operation of the aircraft. For example, at least of one of the heat exchangersis a heat exchanger(s) of the fuel system(s) of the engine(s). In such an example, the fuel system heat exchanger(s)transfers heat from the heat transfer fluid to the fuel supplied to the engine(s). In another embodiment, at least one of the heat exchangersis a heat exchanger(s) in contact with the airflowing through the bypass airflow passage(s)of the engine(s). In such an example, this heat exchanger(s)transfers heat from the heat exchange fluid to the airflowing through the bypass airflow passage(s).

In several examples, one or more of the heat exchangersare configured to transfer heat to the air flowing through the third-stream flow path. In such examples, the heat exchanger(s)is in contact with the air flow through the third-stream flow path. Thus, heat from the heat exchange fluid flowing through the thermal transport busmay be transferred to the air flow through the third-stream flow path. The use of the third-stream flow pathas a heat sink for the thermal management systemprovides one or more technical advantages. For example, the third-stream flow pathprovides greater cooling than other sources of bleed air because a larger volume of air flows through the third-stream flow paththan other bleed air flow paths. Moreover, the air flowing through third-stream flow pathis cooler than the air flowing through other bleed air flow paths and the compressor bleed air. Additionally, the air in the third-stream flow pathis pressurized, thereby allowing the heat exchanger(s)to be smaller than heat exchangers relying on other heat sinks within the engine. Furthermore, in examples in which the engineis unducted, using the third-stream flow pathas a heat sink does not increase drag on the engineunlike the use of ambient air (e.g., a heat exchanger in contact with air flowing around the engine). However, in alternative examples, the heat sink heat exchangersmay correspond to any other suitable heat exchangers that heats a fluid supporting the operation of the aircraft.

Moreover, in several examples, the thermal management systemincludes one or more bypass conduits. Specifically, as shown in the example of, each bypass conduitis fluidly coupled to the thermal transport bussuch that the bypass conduitallows at least a portion of the heat exchange fluid to bypass one of the heat exchangers,. In some examples, the heat exchange fluid bypasses one or more of the heat exchangers,to adjust the temperature of the heat exchange fluid within the thermal transport bus. The flow of example heat exchange fluid through the bypass conduit(s)is controlled to regulate the pressure of the heat exchange fluid within the thermal transport bus. In the illustrated example of, each heat exchanger,has a corresponding bypass conduit. However, in alternative examples, any number of heat exchangers,may have a corresponding bypass conduitso long as there is at least one bypass conduit.

Additionally, in several examples, the thermal management systemincludes one or more heat source valvesand one or more heat sink valves. In general, each heat source valveis configured to control the flow of the heat exchange fluid through a bypass conduitthat bypasses a heat source heat exchanger. Similarly, each heat sink valveis configured to control the flow of the heat exchange fluid through a bypass conduitthat bypasses a heat sink heat exchanger. In this respect, each valve,is fluidly coupled to the thermal transport busand a corresponding bypass conduit. As such, each valve,may be moved between fully and/or partially opened and/or closed positions to selectively occlude the flow of heat exchange through its corresponding bypass conduit.

The valves,are controlled based on the pressure of the heat exchange fluid within the thermal transport bus. More specifically, as indicated above, in certain instances, the pressure of the heat exchange fluid flowing through the thermal transport busmay fall outside of a desired pressure range. When the pressure of the heat exchange fluid is too high, the thermal management systemmay incur accelerated wear. In this respect, when the pressure of the heat exchange fluid within the thermal transport busexceeds a maximum or otherwise increased pressure value, one or more heat source valvesopen. In such instances, at least a portion of the heat exchange fluid flows through the bypass conduitsinstead of the heat source heat exchanger(s). Thus, less heat is added to the heat exchange fluid by the heat source heat exchanger(s), thereby reducing the temperature and, thus, the pressure of the fluid. In several embodiments, the maximum pressure value is between 3800 and 4000 pounds per square inch or less. In some embodiments, the maximum pressure value is between 2700 and 2900 pounds per square inch, such as 2800 pounds per square inch. In other embodiments, the maximum pressure value is between 1300 and 1500 pounds per square inch, such as 1400 pounds per square inch. Such maximum pressure values generally prevent the thermal management systemfrom incurring accelerated wear.

In some examples, the maximum pressure value is set prior to and/or during operation based on parameters (e.g., materials utilized, pumpdesign, aircraftdesign, gas turbine enginedesign, heat exchange fluid, etc.) associated with the thermal management system. The example maximum pressure value can be adjusted relative to the pressure capacities of the thermal transport bus, the pump, the heat exchangers,, the bypass conduit(s), and/or the valves,. Some examples of pumparchitecture that influence example maximum pressure capacities are described in greater detail below.

Conversely, when the pressure of the heat exchange fluid is too low, the pumpmay experience operability problems and increased wear. As such, when the pressure of the heat exchange fluid within the thermal transport bus falls below a minimum or otherwise reduced pressure value, one or more thermal sink valvesopen. In such instances, at least a portion of the heat exchange fluid flows through the bypass conduitsinstead of the heat sink heat exchangers. Thus, less heat is removed from the heat exchange fluid by the heat sink heat exchangers, thereby increasing the temperature and, thus, the pressure of the fluid. In several examples, the minimum pressure value is 1070 pounds per square inch or more. In some examples, the minimum pressure value is between 1150 and 1350 pounds per square inch, such as 1250 pounds per square inch. In other examples, the minimum pressure value is between 2400 and 2600 pounds per square inch, such as 2500 pounds per square inch. Such minimum pressure values are generally utilized when the heat exchange fluid in a supercritical state (e.g., when the heat exchange fluid is carbon dioxide).

As such, the thermal management systemmay be configured to operate such that the pressure of the heat transport fluid is maintained with a range extending between the minimum and maximum pressure values. In some examples, the range extends from 1070 to 4000 pounds per square inch. Specifically, in one example, the range extends from 1250 to 1400 pounds per square inch. In another example, range extends from 2500 to 2800 pounds per square inch.

Accordingly, the operation of the pumpand the valves,allows the disclosed thermal management systemto maintain the pressure of the heat exchange fluid within the thermal transport buswithin a specified range of values as the thermal load placed on the thermal management systemvaries.

Furthermore, the example pumpdrives the flow of the heat exchange fluid through the thermal management system. In some examples, the thermal management systemincludes one pumpor multiple pumpsdepending on the desired flow rate, delta pressure across the pump, and/or the kinetic energy loss of the heat exchange fluid in the thermal transport bus. For example, the pumpmay increase the output pressure head to accelerate the flow of the heat exchange fluid to a first flowrate. As the heat exchange fluid passes through the thermal transport bus, the example kinetic energy of the heat exchange fluid dissipates due to friction, temperature variations, etc. Due to the kinetic energy losses, the heat exchange fluid decelerates to a second flow rate at some point upstream of the pump. If the example second flow rate is below a desired operating flow rate of the heat exchange fluid, then the pumpcan either be of a different architecture that outputs a higher first flow rate, or one or more additional pumpscan be included in the thermal management system.

As disclosed above, the example pumpis important for proper functionality of the engineand subsequently the aircraft. Failure to the pumpcan result in increases in temperature of the fluid, insufficient pressure of the fluid, and/or insufficient fluid flow rate of the fluid moving throughout the thermal management system. Such failures can occur due to bearings within the pumpfailing when the forces acting on the bearings exceed their rated thresholds. As discussed further below, examples disclosed herein provide an improved bearing design to improve the integrity, stability, and reliability of bearings used in apparatus such as the aircraft, engine, and pump.

The operations of some example fluid pump systems and centrifugal fluid pump systems have a rotor shaft connected directly to the impeller in a pump system without a magnetic coupling to connect the rotor/radial shaft and an impeller shaft. In some examples, a bearing is used to support a radial and/or an axial load that a rotor/radial shaft generates, respectively, during operation of the pump system. In some examples, the bearing supporting the radial load can include a foil bearing and the bearing supporting the axial load can include a thrust bearing. A foil/thrust bearing is a form of air bearing that uses a spring-loaded foil between a shaft and a journal lining to support the shaft at low startup speeds. Once the shaft is rotating at a high enough rate (depending on the architecture of the foil/thrust bearing) a working fluid (e.g., air, nitrogen, argon, etc.) is pulled into the foil/thrust bearing due to the viscosity effects of the working fluid. Thus, the working fluid pressure increases in the foil/thrust bearing, pushes the foil outward from the shaft, and supports the radial/axial load that the shaft generates creating a frictionless bearing with no liquid lubricants. Since the foil/thrust bearing does not use liquid lubricants, a hermetic sealing (e.g., a magnetic coupling) may not be used to prevent lubricants from contaminating a fluid (e.g., heat exchange fluid such as a supercritical fluid (e.g., sCO2, etc.)) that the pump system pressurizes.

In some examples, the foil/thrust bearing used to support the radial/axial load that the rotor/radial shaft produces experiences wear during the start-up, stopping, and non-operation of the pump system. More specifically, the spring-loaded foil that supports the weight of the rotor shaft at lower speeds (start-up and stopping rotational speeds) experiences damage over time due to frictional erosion. Additionally, non-operation of the pump purports the same damage possibilities where the aircraftmay cause vibration to the pump system while the aircraftis in operation, causing the rotor/radial shafts to damage the foil/thrust bearings. In the examples disclosed herein, a deformation limiter is disposed in the foil/thrust bearing to limit deformation of the spring-loaded foil during start-up, stopping, and non-operation of the pump system. Thus, the examples disclosed herein limit a radial/axial deformation that the foil/thrust bearing may experience during start-up, stopping, and non-operation of the pump system and reduce damage to the foil/thrust bearings to increase the lifespan (e.g., usable life) of the foil/thrust bearings.

illustrates a cross-sectional view of a pump systemfor pressurizing fluid (e.g., a heat exchange fluid such as a supercritical fluid (e.g., sCO2, etc.)) in a system (e.g., thermal management systemof). In some examples, the pump systemis used to pump sCO2 through a thermal management system on an aircraft (e.g., aircraftof) and/or a gas turbine engine (e.g., gas turbine engineof). As shown in, the pump systemincludes an impeller, a rotor shaft, a rotor, a stator, a thrust bearing, radial shafts, a first integrated bearing system, a thrust bearing assembly, a first sprag clutch, a first bearing housing, a first rolling-element bearing, a first foil bearing, a second integrated bearing system, a second sprag clutch, a second bearing housing, a second rolling-element bearing, and a second foil bearing.